The United States has added Cuba, Libya and Syria to the nations it claims are deliberately seeking to obtain chemical or biological weapons.

Bolton: singled out Cuba for particular criticism

In a speech entitled "Beyond the Axis of Evil", US Under Secretary of State, John Bolton said that the three nations could be grouped with other so-called "rogue states" - Iraq, Iran and North Korea - in actively attempting to develop weapons of mass destruction.

He also warned that the US would take action.

"America is determined to prevent the next wave of terror," he said, referring to the 11 September attacks in Washington and New York that killed up to 3,000 people.

"States that sponsor terror and pursue WMD (weapons of mass destruction) must stop. States that renounce terror
and abandon WMD can become part of our effort, but those that do not can expect to become our targets," he said.

Mr Bush first referred to the "axis of evil" during his State of the Union address earlier this year.

Threat 'underplayed'

Mr Bolton, speaking to the Heritage Foundation, a right-wing political think-tank, also accused Libya of continuing in its attempts to obtain nuclear weapons.

However he singled out Cuba for particular criticism, saying that the country's threat to the US was consistently "underplayed".

"(Cuba) has at least a limited offensive biological
warfare research and development effort (and has) provided
dual-use technology to other rogue states," he said.

Mr Bolton did not indicate that any direct form of military action would be imposed on such countries.

He said the US would primarily concentrate on working with other countries such as China and Russia - "unquestionably the two largest sources of proliferate behaviour internationally" - to prevent the continued dissemination of such weapons, Reuters reported.

The US would also work on smashing the financial networks, suspect shipments and front companies that laundered money for the purchase of such weapons, he said.